UPDATE 2-Hungary's Orban asks European conservatives not to expel his party

Hungarian Prime Minister Viktor Orban has written apology letters to European politicians who called for the expulsion of his Fidesz party from the main European conservative group, but at least one of them said it wasn't good enough. Thirteen conservative parties have demanded Fidesz be expelled from the European People's Party over an anti-immigration and anti-EU campaign that attacked European Commission President Jean-Claude Juncker, a fellow EPP member, and U.S. philanthropist George Soros.

The EPP, made up of the main centre-right parties in most European countries, is the biggest group in the European parliament, expected to keep that status in European elections in May giving it a big say in naming Juncker's successor. According to a copy of one letter seen by Reuters on Thursday, Orban asked the leader of the Flemish Christian Democrats, Wouter Beke, to reconsider his call to eject Fidesz. A Hungarian government spokesman said similar letters were sent to leaders of the other 12 parties who have made similar calls.

"It is no secret that there are serious disagreements... on the issue of migration, the protection of Christian culture and the future of Europe," Orban wrote. "It is also no secret that we do not wish to change our position on these issues." "Yet I do not consider it reasonable to solve such disagreements by expelling a party from our political family. I would therefore respectfully like to ask you to reconsider your proposal for expulsion, if possible."

Orban apologised for referring to critics as "useful idiots", a phrase he said he had borrowed from Lenin and intended to use to refer to policies not individual politicians. Beke said the apology was not good enough: "I accept apologies, but this wasn't about offence given to Wouter Beke," the Belgian lawmaker tweeted. "It was about respect for European values and better cooperation on guarding the EU's external frontiers. I see no change there. The CD&V sticks to its position: no place for Fidesz in the EPP."

LOST HOPE An apology from Orban for offending fellow EPP members was one of several conditions for staying in the group set by the EPP's parliamentary group leader and candidate to succeed Juncker, German politician Manfred Weber.

Orban's strident nationalism and clashes with Brussels have long made him an awkward fit with the mainstream conservatives in the EPP, but both sides have reasons to bury the dispute. Orban has benefited from having a large group in the European parliament protect him from action there, and the EPP gains from an electorally successful central European party in its ranks. Some European conservatives who oppose Orban suspect Weber is bending too far to try to keep Orban in, especially after Weber announced a plan this week to keep Central European University operating in Hungary.

The CEU, which was founded by Soros, is one of Hungary's top universities but says it will be forced to move out of the country by Fidesz law changes. Keeping it open in Hungary is one of Weber's conditions for keeping Fidesz in the EPP. Weber's plan would link up the CEU with a Munich university and the automaker BMW, both based in his German home state of Bavaria. Two senior EPP members of the European parliament who both want Fidesz expelled from the group told Reuters they now consider it increasingly likely the Hungarian party will stay.

"I have lost hope," said one. "It seemed initially Weber's demands were genuine and there was no way Orban would meet them. But now you see Weber is plotting a way out of this for Orban, including engaging Bavarian resources to help the CEU." Weber's office declined to comment.

The EU has long criticised Fidesz over policies it says threaten the rule of law by imposing party control over the judiciary, media and other institutions. Fidesz rejects this. Some European politicians also condemn Orban's attacks on Soros, who is Jewish, as anti-Semitic, which Fidesz also rejects. Anti-establishment and anti-immigrant parties are forecast to surge in the May European elections, often at the expense of older conservative parties such as those that form the EPP. (Additional reporting by Gabriela Baczynska in Brussels, Andreas Rinke and Thomas Escritt in Berlin Editing by Peter Graff)